I’m having the exact same problem. I searched it on google and seen other people are as well, some in different languages as well. But all seem to be having the problem starting today, or been posting about the problem today. I don’t know much about viruses but read some stuff about windows viruses that do something with files that start with “hl” and are bigger then 4 kb but smaller then 2mb and just spread throughout your system and network. It was on the symantec website search tool i searched hl.exe and got a different windows virus then the one that Avast’s WIN32:Steam-AS [trj] definition. Here is the link to symantic search that i read http://www.symantec.com/security_response/writeup.jsp?docid=2003-020612-1237-99&tabid=2.At first i was like right my hl.exe is a virus but after reading that symantec thing, I’m not sure. Again I know nothing about viruses and what they can do I really don’t want to reformat just so I know nothing is wrong, I’m almost positive that this is wrong or a false positive because i deleted the files and steam replaces them when you try to execute a game that needs those files. It still detects the new files steam downloaded as a virus, I’m probably just gunna tell avast to ignore those files but i would like someone who knows what they are talking about to confirm that this is no threat or give some input toward the problem. thanks